1. Field of the Invention
The present invention relates to a surface inspection device and a surface inspection method. More particularly, the present invention relates to a surface inspection device and a surface inspection method for inspecting pattern defects formed on a surface of a sample such as a wafer, or adhesion of foreign matters.
2. Description of the Related Art
In a recent manufacturing process of semiconductor devices, a defect review SEM that inspects pattern defects formed on a wafer, or adhesion of foreign matters (simply referred to as a “defect”) through the use of a Scanning Electron Microscope (SEM) is being used.
The inspection of sample surfaces using such a defect review SEM is performed as follows. First, a defect inspection device such as an appearance inspection device or a laser type surface foreign matter inspection device performs an inspection of a wafer to be inspected, and thereby acquiring data of the inspection results. The inspection data include, for example, the number, coordinates, size of defective spots on the wafer to be inspected, in addition to product number, lot, ID of wafer to be inspected, process inspection device and date. Then, using such review data, the defect review SEM performs, for example, an automatic alignment between the coordinates of a defective spot in the inspection data and those of the surface of the wafer to be inspected, and performs a detailed defect review of the defective spot through the use of an SEM. Finally, the defect review SEM creates SEM image data (image data) of the defective spot. Some defect review SEMs automatically perform the defect classification or elemental analysis on the detected defects.
However, in various surface inspection devices including conventional defect inspection devices or defect review SEMs, the coordinates of the surface of the wafer to be detected are set, for example, only in an area (referred to as an “effective chip area”) where a chip capable of being used as a product is formed. Accordingly, the defect detection can be automatically performed only within this effective chip area.
In an area other than the effective chip area, the following defect detection must be performed aside from the automatic defect detection in the effective chip area. That is, an operator performs an SEM observation by manually turning the wafer to be inspected, using a joy stick or drag ball attached to the defect review SEM. Whenever finding defective spots, the operator records SEM image data or takes photographs thereof.
However, it is difficult for the operator to completely find defective spots on the wafer to be inspected, through these operations. Furthermore, considerable time is required. In addition, the SEM image data or SEM photographs acquired through these operations are not related to the inspection data of the defect inspection device. Therefore, the operator hardly specifies a correct position or generation source of the defects even if he/she can find occurrence of the defects or classifies types of the defects.
Conventionally, the following device is proposed. In order to shorten the amount of inspection time, the device detects the inspection data in a rotary scanning area and in an XY advancing scanning area. The rotary scanning area is an area where the wafer to be inspected is inspected while being rotated in a ring shape or in spirals. The XY advancing scanning area is an area where the wafer to be inspected is inspected while being moved straight in the directions of X and Y. After detecting the inspection data, the device detects the defects in each coordinate position using the data (see, Japanese Unexamined Patent Publication No. 2001-056306).
Conventionally, the following system also is proposed. In order to reduce the operation quantity of an operator, the system has a configuration that an optical review device performs a preliminary inspection of a wafer to be inspected, and a defect review SEM performs a detailed inspection of the wafer using preliminary inspection information as the inspection data acquired through the preliminary inspection. The system has a data base that stores review information acquired through the review of the defect to be reviewed, which is selected from the defects included in the preliminary inspection information (see, Japanese Unexamined Patent Publication No. 10-135288).
In an effective chip area of a wafer to be inspected in a manufacturing process of a semiconductor device, elements or wiring patterns are generally formed densely. Therefore, the following problem is raised. Even when defects such as pattern peeling or adhesion of foreign matters, for example, particles are found within the effective chip area by defect detection, it is difficult to specify the generation source or to investigate the generation cause only by the information in some cases. When the surface of the wafer to be inspected is gradually inspected in more detail, the source of these defects is considerably found in an area other than the effective chip area, which heretofore stands outside the area to be inspected for the defect inspection.